1. Field of the Invention
The present invention relates to a technical field of a film deposition apparatus which deposits a thin film by laminating reaction products by sequentially supplying process gases, which mutually react, onto the substrates while the substrates are orbitally revolved.
2. Description of the Related Art
As one of film deposition techniques in a semiconductor manufacturing process, there is an Atomic Layer Deposition (ALD) method. According to this ALD method, a plurality types of process gases (reaction gases), which mutually react, are sequentially supplied on the surface of a semiconductor wafer (hereinafter, referred to as a wafer) to thereby laminate reaction products. A known film deposition apparatus, with which a film is deposited by the ALD method is structured such that a turntable, on which a plurality of wafers are mounted so as to be arranged in a peripheral direction, are orbitally revolved around so that the wafers sequentially pass areas where process gases are supplied. This film deposition apparatus includes a separating area, into which a separation gas including an inert gas, for example, a nitrogen gas is supplied, in order to prevent a plurality of processing gases from being mixed in the rotational direction of the turntable (to separate the process gases). An exemplary plurality of process gases is a raw gas to be absorbed on the wafers and a gas for oxidizing or nitriding the raw gas.
When the separation gas flows into an area supplied with the raw gas along with the rotation of the turntable, the raw gas is diluted by the separation gas and in-plane evenness in the film thickness is degraded. To deal this, the flow rate of the raw gas is required to be increased. Therefore, the cost increases. Japanese Laid-open Patent Publication No. 2011-100956 discloses a structure that a current plate is provided over a gas nozzle which extends in a radial direction of the turntable and a separation gas flows in a supplying area into which a raw gas is supplied after the separation gas overleaps the current plate.
By providing the current plate over the gas nozzle, it is possible to improve adsorption efficiency of the raw gas onto the wafer even though a supply flow rate of the raw gas is reduced.